The present invention generally relates to drain clearing devices. More specifically, this invention relates to drain clearing devices which provide both positive and negative pressures to dislodge or remove foreign objects.
The most generally known type of drain clearing device is the hand-operated plunger comprising an elongated handle having a resilient, inverted-cup-shaped member secured to one end of the handle. By repeated collapse and release of the inverted-cup-shaped member while disposed in sealing engagement pressure under the member create an agitation that tends to dislodge clogging particles or foreign objects. The limited volume of air that can be trapped under the inverted-cup-shaped member renders this hand-operated plunger ineffective for removal of tightly-wedged clogs or large foreign objects.
Various means to improve the effectiveness of hand-operated plungers are disclosed in the prior art. U.S. Pat. No. 2,498,359 to Coleman discloses a hand-operated plunger device formed with a bore in the handle which receives a tube and a slidably supported valve-carrying body disposed in the tube. Selective positioning of the valve-carrying body above and below ports formed in the tube and handle permits selective use of the device as a pump or a plunger. U.S. Pat. No. 2,697,842 to Meyer discloses a combined hand and forced air pressure pump and plunger. The Meyer device can be used either as a pump, or as a plunger, by forcing trapped air from the device through a clogged drain A spring-loaded plunger is disclosed in U.S. Pat. No. 4,733,414 to Wilkes.
Another type of drain clearing device known in the art generally comprises a cylindrical body having a retractable piston plunger which draws water into the cylindrical body or forces water therefrom to dislodge a clog in a drain. In U.S. Pat. No. 2,456,092 to Storevik a drain clearing device of this type is disclosed which includes a pair of arcuate outlet pipes at an end of the cylindrical body which converge to an end pipe. A collar adapted to project from the end pipe into the clogged drain holds the device centered U.S. Pat. No. 3,641,597 to David et al. discloses a drain clearing device having a tubular body and a piston and rod assembly disposed therein. The piston of the assembly comprises a pair of adjacently-disposed frustoconical rubber rings. U.S. Pat. No. 3,934,280 to Tancredi discloses a further drain clearing device having a cylindrical body and a retractable piston plunger. A circumscribing radially-outwardly and upwardly flared flange is attached near the lower end of the cylindrical body to facilitate seating of the device in a drain. U.S. Pat. No. 4,186,451 to Ruo discloses an all-plastic drain clearing device of the retractable piston plunger type. In U.S. Pat. No. 4,674,137 to Girse a drain clearing device having a cylindrical body and a retractable piston plunger is disclosed which further includes controllable flutter type seals disposed on openings formed in the piston to adapt the device for selective conduction of positive or negative pressure forces through the clogged drain A lateral outlet pipe is attached to the top portion of the cylindrical body for discharge of fluid and debris removed from the drain.
While the drain clearing devices of the prior art provide means for selective development of positive and negative pressure forces, none of the references cited provide sealed visual means for observing when a foreign object or clogged debris is removed from the drain. Thus, to determine if a drain is unclogged the prior art devices require continual removal of the device from the drain, checking of the drain flow, for example by flushing a commode, and subsequent repositioning of the device in appropriate sealing engagement The inefficiency of this method of clearing a drain is costly, in particular where commercial plumbers and the like are utilized The prior art drain clearing devices also generally function to loosen a clog instead of completely removing the clog from the drain, in part because it cannot be readily determined when the clog has been removed. Complete removal of a clog from a drain prevents further obstruction of the drain through subsequent re-entry of the clogging debris or foreign object. Prior art drain clearing devices also splash water during unclogging operations which necessitates cleaning of the surrounding floor and inhibits operation of the device when the user is nattily attired A further limitation of the prior art drain clearing devices is the failure to maintain sealing engagement of the device with the surface surrounding the drain. These and other limitations and disadvantages of the prior art drain clearing devices are overcome by the drain clearing device of the present invention.